Probably should've read the entire post before I quoted it.
But my point is, for being "full" 64-bit, I want 64-bit kernel on my macbook air, which I can't do. Bit disappointing.
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Snow Leopard has a 32-bit kernel! as the default
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Probably should've read the entire post before I quoted it.
But my point is, for being "full" 64-bit, I want 64-bit kernel on my macbook air, which I can't do. Bit disappointing.
Why do you want a 64 bit kernel on your MacBook Air?
I would suspect your answer to be: "Because it's a 64 bit kernel?"
Look, the MacBook Air doesn't even have enough RAM for applications to take advantage of 64 bit apps, let alone the kernel. You would not notice any advantage other than being able to say "I can run K64! Yay!"
Mac OS X already supports PAE (Physical Address Extension) mode on IA32 to allow 36 bit addressing so you could theoretically have 2^36 bytes (or 65536 megabytes (or 64 gigabytes)) of RAM and utilise a 4 gigabyte block of this in a 32-bit PAE aware application.
However, Snow Leopard should perform a little better with the 64 bit kernel due to the architectural improvements in the AMD64 extensions to IA32:
- 64 bit integer registers
- 16 GPRs rather than 8. For reference PPC had 32. This'll reduce stack access significantly (and therefore cache and memory hits.) This was a big bottleneck in the IA32 ISA.
I'm not really sure exactly what scale of performance improvements the 64-bit kernel would bring but its probably worth having...
I'm betting that Apple will enable this on all 64 bit Macs as we go through the 10.6.x point releases.
Yup, found plenty of posts similar to yours on various forums that claim that everything will be fine for PPC apps / Rosetta under SL, but don't list a specific PPC app that they've actually TRIED it with. Could you be more specific, and perhaps name a PPC-only app that you've actually run under SL? Quicken would be a great example, as even Quicken 2007 is PPC-only, but really, any PPC-only app would work as a concrete proof of claim. Thanks!!!
No. It's because the 64-bit kernel will show some, no matter how minor, speed improvements in day to day uses. The system's fast with the SSD, but thats only for loading/opening/closing programs, nothing else. Any little performance boost out of the Air would be a big bonus for its size/weight/design.
What are you on about, are you saying Rosetta doesn't work? I downloaded Power64 which is PPC only. SL prompted me to install Rosetta and it now runs fine.
Thank you.
You tried a specific PPC-only app under SL and confirmed that it worked, and posted your finding. Much appreciated! As for "what I was on about" was specifics, not vague "sure it'll work fine" generalities. And you've provided a specific, concrete answer. You tried a real app on a real system, it really worked, question answered.
And no, until you answered the question, I (and many other people without early access to SL) had no definite idea
if Rosetta would continue to work under SL. That's why I was asking. It's good to know for sure before doing an update.My 09 3.06 uMBP did not have 64 bit on by default upon upgrading. Had to do the 6+4 trick and then everything was good to go.
P.S. What difference does it make if its on by default or not? I think we can all pretty much agree that only us geeks care. 95% of users will have no idea what 32 vs 64 even means. If you are in the 5% who cares then you know how to find the trick to turn it on in about 10 seconds.
P.S. What difference does it make if its on by default or not? I think we can all pretty much agree that only us geeks care. 95% of users will have no idea what 32 vs 64 even means. If you are in the 5% who cares then you know how to find the trick to turn it on in about 10 seconds.
Only Xserve will run 64-bit kernel by default, nothing else according to the official release notes.
Tried on my mid-2009 MBP 15" and it's default to 32-bit kernel. Enabling the 64-bit kernel with the boot configuration change is pretty trial. But some applications, such as VMware Fusion refuses to run on the 64-bit kernel.
They won't be.
The kernel was designed to be a small piece of software, there probably isn't much room for it to take advantage of the extra registers. And any performance improvement would only be seen when using kernel functions. You generally wouldn't see performance improvements in stuff like Photoshop or Final Cut Pro.
Err so what's the point of 64bit?
More RAM, etc. A Google search might give you more specific results.
Err so what's the point of 64bit?
For the kernel, more addressable space. We don't need more space now, but the idea according to Apple is that we'll need it in the future, which is kind of what Snow Leopard was about... When we have stuff like 8 gig graphics cards, the kernel will need enough space to address all that VRAM.
For applications, especially in video processing and image processing, the additional 64 bit registers can speed up processing. But the kernel doesn't really do anything like that. And the 64 bit kernel and 64 bit applications are entirely separate technologies.
Wrong. The official release notes are inaccurate. My 17" uMBP boots into the 64-bit kernel by default(which did surprise me). I double-checked under activity monitor and all default apps(finder, ical, etc) run under Intel(64-bit).
I'm on my mid-09 Unibody 15" and most of my apps say Intel (64-bit) as well, even though I'm running on the default 32-bit kernel. If you're running in 32-bit mode, as I am, your Activity Monitor will look something like this under "kerneltask"
Attachments
No. Kernel Task doesn't say 64 so I'm guessing it's not. But isn't the OS still running on the 64-bit architecture, since 64-bit apps are working and running in 64-bit mode(safari, tweetie, quicktime, finder, etc)? Or am I mistaken?
Running 64 bit apps is entirely different than running 64 bit kernel. The 32 bit kernel can run 64 bit apps.
Leopard can run 64 bit apps as well. It's just that Apple didn't include any.
I was wondering as well. Since Applications can already run in 64-bit, what kind of performance gains would one see with a 64-kernel?
Actually it does not use PAE. OS X places the processor in the sub-mode of 64-bit mode to support large amounts of RAM.
You'll probably never see anything. The only area that will see an improvement will be user/kernel memory copy (read/write).
Although, this is extremely minor for nearly everyone who visits MR.
It means that if the kernel itself uses more than 4GB of ram* (which basically only happens in machines with 30-40GB or more of ram), it won't crash. This is by far the biggest reason to have a 64 bit kernel.
As an added benefit, it speeds up a small number of operations, which may or may not speed up any applications you care about. Highly unlikely to be noticeable.
*to see how much ram your kernel is using, find kernel_task in activity monitor, and look at the Real Mem column. Mine is using 235MB at the moment, with 3GB of ram installed.
Correct, or a lot of VRAM.
Put quite simply: There is no reason you'd ever need to use K64 on a modern machine, especially on a Macbook Pro with already limited expansion.
It was added as something to give developers a head start in writing 64 bit drivers, and as a way to be ready for years in the future when we have epic machines with lots of VRAM and RAM. People need to stop worry about it. You likely will never need it on the machine you have in your hands now.
My guess is that the XServes boot K64 as the default so that Apple can force developers to write 64 bit drivers for customers without inconveniencing a major portion of their users. The kernel improvements might also be felt more by web and database servers, but likely it still wouldn't be a huge improvement.